Soft pedal after New brake pads, rotors, and SS lines - WTF!

[Glenn_03Cobra]

I don't know what the problem is...
Installed new rotors, Hawk pads, and front SS lines on my '03 Cobra but, now have a soft pedal. We double and triple checked the install. Bled the brakes atleast 6 times on Friday activated the ABS during test drive then bled them again on Saturday 4 times. We tapped on the lines, ABS, and calipers to try to rattle loose some air. We mostly used a Motiv pressure bleeder but a couple of times bled manually with one guy keeping the m/c full, one pushing the pedal, and one working the bleeder. During each bleed, we varied how much fluid we let out each time and fluctuated the bleeding screw from small streams to full stream.

The pedal grabs the brakes close to the floor but there's nothing for about half a pedal before I notice anything. The pedal does not sink, when holding and pumping the pedal doesn't change anything. After 10 - 15 (lost count) bleeds, it feels the same as it did after the first bleed.

The only thread I found on this forum, relating to a similar bleeding brake problem was ->http://www.svtperformance.com/forums/showthread.php?t=513977.

I'm thinkin' there is a malfunction in the system somewhere.

Anyone have any ideas? :shrug:

 

[04cobrasvt]

you most likely have alot of air built up in the ABS pump. You may need to bring it to ford or a shop that has a scanner that activates the abs as your bleeding the brakes to insure all the air is out.

 

[Blind]

is there a way to manually activate the abs pump by jumpering the ABS relay?

and yeah, we bled through about 7 quarts of dot 4 fluid with the pressure bleeder, tried 10psi, 15psi, and 20psi at different bleed attempts.

there's gotta be air somewhere.

 

[slitherin' 03]

you most likely have alot of air built up in the ABS pump. You may need to bring it to ford or a shop that has a scanner that activates the abs as your bleeding the brakes to insure all the air is out.

+1

By the way, it's spelled "fluctuated." :beer:

 

[Glenn_03Cobra]

+1

By the way, it's spelled "fluctuated." :beer:

:-D it's been a long weekend already!

 

[cobraracer46]

No need to mess with Antilock module because it only needs to be bled when it has ben replaced. There is air in the master cylinder so bleed that.

 

[Blind]

No need to mess with Antilock module because it only needs to be bled when it has ben replaced. There is air in the master cylinder so bleed that.

we bled that 3 times.

 

[ShelbyGuy]

then you're doing it wrong, because thats where your air is.


you *must not* let the master cylinder reservoir run dry otherwise it will suck air.

put a hose on the end of the forward-most bleeder screw on the master cylinder. put the other end of the hose into the master cylinder reservoir, with the end below the level of the fluid. pump brake pedal until the bubbles go away. repeat with the bleeder screw closer to the firewall.

then pump about a pint through each caliper. don't complain about the price, because unless you're using castrol srf, nobody wants to hear it start with the caliper farthest away from the master cylinder, which is passenger side rear. bleed it until you get new fluid with no air. then do the drivers side rear, then passenger side front, then ddrivers side front. always work from farthest away from the master cylinder to the closest. if you have fixed front calipers with two bleeder screws, start with the outer bleeder screw first, and then do the inner second.

even if you did get air in the abs hcu, you wouldn't notice it until the abs servo cycles. there is minimal fluid inside the abs hcu, and it would trap the air with it until the car noticed a lock-up condition and released that fluid holding the air, as it cycles.

 

[2003snake]

then you're doing it wrong, because thats where your air is.

+1

 

[Glenn_03Cobra]

Gave up and took it to the dealer today. They hooked it up to their equipment and a laptop to activate the ABS to bleed it. The tech said he found that the ACU had air in it. What was interesting was, after they finished, I had stong pedal, when car was off but still a very soft pedal, when running.

When I got home (after driving around town for awhile) I pumped the brakes a few times, hard. When done, the pedal came-up and finally wasn't soft... I think it should be harder but, it's much better than when I left the dealer. I also have a strange squeek or high-pitch blow-by sound, when I hit the brakes hard. I compared to another Cobra setup and it was quiet (except for the p/s).

I find it strange that after pumping it hard, I have more pedal consistently, when before pumping it hard, there was no pedel for the top 60% or so then it was soft; only the bottom 10% seemed to have bite on the brakes. What did I do that the dealer wasn't able to do. I'm a bit leary that they thought the brakes were ok, when I left.

This dealership has always done good work for me, when my service writer is controlling the work. This time, IMO they dropped the ball. We'll see what they say, when I go back in tomorrow!

 

[Cobrakai04]

keep us updated. I am bleeding my brakes soon and adding new pads,rotors and lines and would like to avoid any problems.. So do you think the air got in from the reservoir?

 

[Blind]

there's no air in the master, it never ran dry and we stopped getting air out long before we went through the 7th quart of brake fluid using a motive pressure bleeder.

 

[ac427cobra]

How long was the hydraulic brake system 'open' for this project?

 

[Glenn_03Cobra]

Unfortunately :bash: I didn't block-off the lines, while the calipers and old lines were off for the cleaning. They were open for probably 30 - 60 minutes. However, since we bled every frickin thing that can bleed and ran so much fluid through with the pressure bleeder (read original posts), you would think it would have done the trick.

 

[Glenn_03Cobra]

keep us updated. I am bleeding my brakes soon and adding new pads,rotors and lines and would like to avoid any problems.. So do you think the air got in from the reservoir?

No... I think I screwed-up by not blocking-off the lines, when the calipers were off. It may have been enough time to allow fluid to draw from the ACU. I'm taking it back to the dealer this afternoon but, not sure they will have any answer as to why hard pumping after I left the dealership yesterday brought the pedal up to where it belongs.

 

[ac427cobra]

Unfortunately :bash: I didn't block-off the lines, while the calipers and old lines were off for the cleaning. They were open for probably 30 - 60 minutes. However, since we bled every frickin thing that can bleed and ran so much fluid through with the pressure bleeder (read original posts), you would think it would have done the trick.

Ok, that wasn't a very long time at all. As long as the master cylinder didn't get drained, some air bubbles could have made their way up into the ABS system. Most likely from the right front?!?!

If you have the chance and your brakes are good enough to drive on the street, get out on a rainy day and cycle the bejeebers out of your ABS system and re-bleed. If that doesn't do it on the first attempt, repeat. If it still doesn't do it you're going to have to go to the Ford dealer and have them bleed the system and use their tool to cycle the ABS system. That should do it.

I know it's a little late for you but others should know it's very important to leave your braking system 'open' for as short a period as possible when changing lines, calipers or whatever.

FWIW


:thumbsup::coolman::beer:

 

[Glenn_03Cobra]

But, it doesn't rain in So Cal :rolling:

We activated the ABS with several hard stops and re-bled over the weekend; hence, my follow-up post that I took the car to the dealer. What I'm trying to understand now is why a reputable dealer and brake tech would tell me that after they said they fixed the bleed problem that the pedal still didn't feel right until I later pumped the pedal hard.

I think the best advice is to use line plugs, when the hose is disconnected.

 

[racebronco2]

The biggest problem people have is that they get air in the system and when they do bleed the lines the bubbles move done the line but as soon as they close the bleeder the air works itself up the line and this is done over and over again. The first time i used a couple of bottles of motul 600. I figured out to i needed to let the car sit overnight when you bleed the master cylinder so the air works itself up to the reservoir.

 

[Glenn_03Cobra]

The car sat overnight and we activated the abs several times before it sat. It appears that the problem we had is not very common; hence, the reason why so many don't understand how we could have had the problem in the first place. However, when it happens, it's a real bear to deal with. But, I'm glad it happened to me... I learned a lot from this experience!

Thanks for all the comments and advice guys, I do appreciate it!!

 

[Jomo1994z71]

brakes on Terminators are a PITA, especially gettin the air out